Video games such as action games and role-playing games make characters act in a virtual game space corresponding to operation input by users. In such games non-player characters, for example enemy characters attacking a player character, appear in addition to the player character. Actions of the non-player characters are not operable directly by user's input. And the non-player characters are controlled to make act accordingly to the predetermined rules in the virtual game space.
For example, in the game progressed with fighting against enemy characters, it may be known such configurations as setting difficulty of the game before the game starts. For example, the difficulty is set so that parameters of a non-player character, such as attack value, defense value, dodge, way of attacking, experience point, and/or drop item obtained when the non-player character has been broken-down, can be changed. Therefore, the higher the difficulty is set, the more difficult the game becomes. Consequently, when the difficulty is set the higher, the higher technic is required.
Also game systems such that the plurality of users is able to join the game in the virtual game space via network may be known. For example, patent literature 1 shows game systems that some of the users are handicapped if there is a technical gap among the users when the plurality of users plays a match. In such game systems, users can enjoy playing game regardless of the technic.